Unusual Compressional Behavior of Lithium–Manganese Oxides: A Case Study of Li₄Mn₅O₁₂

Lithium-rich spinel oxide has been synthesized in a long-term low temperature sintering process via the intermediate defected phase. Synchrotron X-ray diffraction studies under pressure have been performed on Li 4 Mn 5 O 12, and some similarity of its behavior under compression to that of LiMn 2 O 4 has been demonstrated. Li 4 Mn 5 O 12 reveals a bulk modulus value of K 0 = 118(1) GPa, and K 0 ′ = 4.5(3) GPa. This value is far below 200 GPa, which is typical of most spinel oxides. The local compressibility of LiO 4 tetrahedra is responsible for these unusual elastic properties of lithium–manganese spinel oxides both with Mn 4+ only and Mn 3+ /Mn 4+ ions in octahedral sites.